1. Field of the Invention
The present invention relates to an electronic circuit device in which electronic components such as semiconductor memory are bare-chip mounted, and, for example, relates to a COB (chip on board) type electronic circuit device.
2. Related Background Art
In accordance with the trend toward compact, lightweight, and portable electronic equipment, there is an increased demand for a compact and lightweight electronic circuit device in which electronic components such as semiconductor components are mounted on a board. As the electronic circuit device for a compact configuration, a COB type semiconductor device is known, for example, in which a semiconductor element is bare-chip mounted on a board.
In the COB type semiconductor device, a semiconductor chip is mounted on the board via a die bonding material. A conductive wiring is provided on the board, and an internal terminal at one end of the conductive wiring and an electrode provided on the semiconductor chip are connected via a metal wire. The semiconductor chip and the internal terminal are encapsulated with resin.
In a manufacturing process for a conventional COB type electronic circuit device, an encapsulation resin for encapsulating the semiconductor chip, etc., is applied by potting. Therefore, since there is no means for controlling the spreading of the resin, the wettability and the spreadability of the resin vary greatly depending on the viscosity, the applied amount and the temperature of the resin, the condition of the board and the like. As a result, it is difficult to control an applied area of the resin to be constant, so that there is a limitation on the miniaturization of the products and a cost is high.
In order to solve this problem, JP H09(1997)-162208 A and JP H10(1998)-92968 A show a method for blocking a flow of an encapsulation resin by forming a printed bank on the periphery of a region for packaging a semiconductor chip, the bank protruding from a surface of a board.
However, since in the above conventional example, a new element is used for forming the bank to control the flow of the encapsulation resin in addition to ordinary constituting elements, the manufacturing cost will be increased. Also, by adding the extra element in addition to the original constituting elements, there is a risk of a decrease in reliability. For instance, in the case where the bank for controlling the flow of the encapsulation resin is formed with a resist coat, and if there is a portion of the resin bank overlapping a Cu wiring, it becomes difficult to cover the Cu wiring with Ni/Au plating at an edge of the coat. Therefore, there may be a deterioration in the anticorrosion capabilities of the wiring.